如何理解链表中的双指针

Question

i found a useful page which explained how to use double pointers in a linked list .

But there are a few points that i could not understand.

void AddNodeSorted(node* pNewNode)
{
  node** ppScan = &pRootNode;
  while(*ppScan != NULL && compare(*ppScan,pNewNode))
    ppScan = &(*ppScan)->pNext;

  pNewNode->pNext = *ppScan;
  *ppScan = pNewNode;
}

In this function, I could not understand how the last two lines work. In my point of view, after the while loop , the new item needs to insert before the element which ppScan indirectly points to.

So pNewNode->pNext = *ppScan works alright. Then what's the meaning of *ppScan = pNewNode ? pNewNode->next = pNewNode ??

Answer 1

since "ppScan = &(*ppScan)->pNext;","*ppScan = pNewNode;" will let the last element to point to the new node.